Maximus conducts the same war ritual four times in the film: he picks up a small quantity of the ground beneath his feet and rubs it between his hands. He also smells his hands after rubbing them but this is only seen in the first two occurrences. He does so each time before he is involved in combat. These are:
1. Before the start of the opening battle sequence in Germania, while he is talking to Quintus.
2. Before the start of his first gladiator fight in Zucchabar, while Proximo gives the pep talk.
3. Before the start of his first gladiator fight in Rome (the Colosseum), while in the armoury.
4. Before the start of his first duel in the Colosseum with Tigris of Gaul.
5. Very weakly before the start of his final duel in the Colosseum with Commodus.
The practical reason for conducting this ritual is to make friction (by absorbing the sweat) between his hands and the object he is holding: it is to form a better grip on his sword, like chalk. The personal reason is to remind Maximus of his villa, which is full of rich memories of the harvest, his wife, his son, his horses and general actions akin to the soil. Director Ridley Scott points this out during his DVD commentary. During the victory celebration after the battle in Germania, there is conversation between Maximus and two of his officers which relate to his villa:
Valerius: Back to your barracks, General, or to Rome?
Maximus: Home. The wife, the son, the harvest.
Quintus: Maximus the farmer. I still have difficulty imagining that.
Maximus: You know, dirt cleans off a lot easier than blood, Quintus.